JPS63170253A - Glass/poly(carboxylic acid) cement composition - Google Patents

Abstract

A process for producing a radiopaque cement comprises reacting a polymer containing free carboxyl groups (generally a homo or copolymer of acrylic acid) with a particulate acid-leachable source of polyvalent metal ions (such as an acid-leachable glass) in the presence of water and strontium fluoride.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in glass/poly(carboxylic acid) compositions and to glass/poly(carboxylic acid) compositions.

Glass/poly(carboxylic acid) cement compositions are well known and established.

Such compositions essentially consist of (i) a polymer containing free carboxylic acid groups (typically a homopolymer or copolymer of acrylic acid) and (it) a source of acid-leachable polyvalent metal ions [e.g. Acid leached glasses such as calcium fluorosilicate glasses (laachab
It is composed of [legglass]]. In such a composition, in the presence of water, the polyacid leaches polyvalent metal ions from the polyvalent metal ion source and these serve to crosslink the polymer molecular chains to give a solid material (cement). Materials have been subject to reliable professional discussion, such as “Organolith polymeric materials.”
ic Macro-molecular Materi
alg), Author Ni, Dee.

Wilson (A, D, 11ilson) and Niss, Crisp (S, Cr1spL Applied Science Publishers (Appl.
iedScience Publishers), 1
977 (see especially Chapter 4).

Glass/poly(carboxylic acid) cement compositions are used as dental restorative materials.
It has been found to have special uses as a material, but its practical drawback is that it is radiolucent, essentially making it a hindrance to transmit X-rays. As a result, for example, it becomes impossible to examine dental restorations made using such compositions with X-ray techniques, and furthermore, dental restorations that may be moved or swallowed by a person are Any part, X
It becomes impossible to ascertain its whereabouts using line technology.

The radiopacity of a tooth material (ie the extent to which it absorbs X-rays) can be conveniently defined by the thickness of aluminum (mm) which has the same radiopacity as 1 mm of tooth material. Typical values for enamel are 1.3-2.7 mm of aluminum per mm of enamel, and for dentin 0.6 mm of aluminum per mm of dentin.
-2, 0 mm.

According to the present invention, a radiopaque cement can be produced from a composition comprising a polymer containing free carboxyl groups, an acid-leachable source of polyvalent metal ions and water, and further comprising strontium fluoride. That's what I found out. Strontium fluoride is currently the predominant radiopaque agent, providing essentially all radiopacity, even in the presence of other substances that have other, slightly radiopaque properties. Furthermore, the use of strontium fluoride provides an optically clear hardened cement (similar to the hardened cement that would be obtained in the absence of strontium fluoride), which makes the hardened cement of the present invention useful in dental restorations. What makes it valuable has been discovered. This translucency is due to CI
When expressed in terms of L7° value, it is suitably less than 0.7, preferably less than 0.6 and most preferably 0.5.
It is as follows.

According to the invention, therefore, a crosslinked cement is produced which consists of reacting a polymer containing free carboxyl groups with a particulate source of acid- or alkali-leachable polyvalent metal ions in the presence of water and strontium fluoride. You will be given a way to do so.

In order to achieve satisfactory radiopacity in use, strontium fluoride is suitably used in a proportion of 7 to 7 %, based on the total weight of the polymer containing free carboxyl groups, the acid-leachable polyvalent metal ion source, and the strontium fluoride. .5 to 50
Preferably from 15 to 33%, more preferably from 19 to 23% by weight.

The source of polyvalent metal ions can be, for example, an acid-leaching glass such as a calcium aluminofluorosilicate glass, which preferably contains 9 to 25% by weight of calcium (calculated as CaO); aluminum (AQ, O, ) 28 to 38% by weight Silica (Sin
, calculated as ) 25 to 30% by weight; and fluorine (calculated as
F, calculated as ) 0 to 12% by weight; and phosphorus (P
*calculated as Os).For convenience, the multivalent metal ion source will be referred to simply as "glass" hereinafter. As will be appreciated, strontium fluoride itself can serve as a source of multivalent metal ions.

Polymers containing free carboxyl groups are preferably
It is an acrylic acid homopolymer.

Acrylic acid copolymers can also be used, but homopolymers are preferred [D.

J, Setchell (D, J, 5etchell
) and collaborators, British Dental Journal (B rftis
hDental Journal), 1985,
158, p. 220], the acrylic acid polymer or copolymer suitably has a molecular weight of between 20,000 and 125.
000, preferably 35,000, preferably 35,000,
000 to 7o, ooOl and most preferably 4
For convenience, polymers containing free carboxyl groups having molecular weights ranging from 5,000 to 55,000 will be referred to hereinafter simply as "polyacrylic acids".

The glass must be in particulate form.

Suitably they have a particle size in the range 0.5 to 60 μm. The particle size of the glass can vary within these ranges depending on the intended end use of the composition. Thus, for example.

If the composition is to be used as a simple dental restorative material (i.e. a filling or sealing material), a particle size of 1 is suitably 0.
．． in the range of 5 to 40 μm, preferably 1 to 3
0 μm, most preferably in the range of 2 to 20 μm;
and sub-fillers, bases or backings (
For use as a liner), the particle size suitably ranges from 2 to 60 μm, preferably from 2 to 40 μm.
, and most preferably in the range of 5 to 30 μm.

The weight ratio of polyacrylic acid to glass is suitably from 0.15:1 to 0.5:1, preferably 0.15:1 to 0.5:1.
2:1 to 0.3:1 and the weight ratio of water to glass is suitably between 0.2:1 and 0.2:1.
5: 1. Preferably it is about 0.25:1.

The reaction of polyacrylic acid and glass can be carried out in the presence of other substances that serve to change or adjust the processing and/or curing times of the mixture,
Hydroxycarboxylic acids, such as tartaric acid, have been useful in increasing the curing rate of the composition without affecting processing time.

A composition for forming a solid cement from glass, polyacrylic acid and strontium fluoride can be presented as a two-component pack, in which the -component is an aqueous solution of polyacrylic acid (optionally a treatment/hardening time regulator). ), and other components include strontium fluoride and fine glass particles. Alternatively, a dry mixture (triblend) can be made up of particulate glass and powdered polymer and strontium fluoride, to which water is subsequently added to yield a cement-forming composition.

The cementitious agents produced according to the present invention are generally radiopaque and they are particularly used as base-fillers, substrates or liners under the so-called composite filler materials mentioned above. It was found to be suitable.

A wide variety of such composite filler materials are known or proposed. These more commonly used materials are polyethylene-based unsaturated polymers or oligomers (
For example, bis-0MA or a derivative thereof or urethane diacrylate), an ethylenically unsaturated component (for example, ethylene glycol dimethacrylate), a filler, and a polymerization initiator. Typical fillers are glass ceramics or particulate quartz with particle sizes ranging from 1 to 80 μm, or borosilicate glasses and/or colloidal silica with particle sizes ranging from 0.005 to 0.2 μm. The initiator can be an initiator that operates at room temperature, such as benzoyl peroxide and a tertiary amine, or it can be an actinic radiation sensitive initiator, such as benzophenone or camphorquinone.

Thus, in another embodiment of the invention, a base, liner or subfiller is formed according to the method of the invention, and then one or more ethylenically unsaturated compounds, particulate filler and ethylenically unsaturated A dental restoration method is provided that comprises forming an overlaying filler on a base from a composite dental composition comprising a polymerization initiator for the compound.

Strontium fluoride can be used according to the invention as a radiopaque agent in other dental restorative materials, such as the composite materials mentioned above. In particular, strontium fluoride can be used in composite filler materials and in pit and tissue sealants, where the caries-inhibiting effects of fluoride on ions are particularly desirable, and strontium fluoride The radiopaque effect of strontium can aid in the diagnosis of recurrent caries.

In broader terms, the present invention provides resin structures that include strontium as a radiopaque agent, preferably as the primary or only radiopaque agent. Such structures, which are preferably translucent, have a radiopacity of at least 1.0 mm of aluminum per mm of structure, preferably at least 1.5 mm, and most preferably at least 2.0 mm of aluminum per mm of structure. Have it in place. Such structures are suitable for use in dental restorative methods.

In order that the invention may be better understood, the following examples are given by way of illustration only. In the examples, all percentages are 1 weight percent unless otherwise indicated.

Leave! tU Cement-forming powder was mixed with (a) 62.1% by weight fine-grained calcium fluoroaluminosilicate glass (commercially available as Chemfil) with a sorter mean diameter.
) 5 μm, (b) 15.1% molecular weight 45
,000, (c) 1.3% tartaric acid, and (d) 21.5% strontium fluoride.

The powder was mixed with water by hand using a dental spartil and a glass block at a powder/water ratio of 6.8:1. The resulting cement has a typical working time of 3 minutes at 23° C. and a radiopacity of 2.5 mm of aluminum/mm of cement.

The compressive strength was 182 MPa, the surface strength was 15.3 MPa, and the solubility was 0.25%.

J42Lu powder was prepared in the same manner as described in Example 1, except that it contained 69.3% powdered glass and 14.3% strontium fluoride. The same powder was evaluated in the same manner as described in Example 1, with a typical working time of 2 minutes at 23°C, a compressive strength of 204 MPa, and a radiopacity of 1.0 mm of aluminum/mm of cement.
It was found to be 4 mm.

Abortion-1 10 grams of a resin containing 2 moles of hydroxypropyl methacrylate and 5 parts of a urethane adduct from trimethyl-hexamethylene diisocyanate are dissolved in 10 grams of triethylene glycol dimethacrylate. 0.03 g of camphorquinone and 0.2 g of methyljetanolamine were dissolved in
Finally, 15 g of strontium fluoride with a particle size of less than 10 μm are dispersed in the same solution. The resulting composition was mixed with Pris+*alite (Dentsply Inc. L, D, r-, =1-)) Divisimin (L, D, Cau).
Polymerized by irradiation for 20 seconds with actinic radiation using a product of LK Division) to give a radiopaque composition suitable for sealing pits and cracks.

Claims (1)

Claims: 1. A method for producing a crosslinked cement comprising reacting a polymer containing free carboxyl groups in the presence of water and strontium fluoride. 2. Strontium fluoride is present in an amount ranging from 7.5 to 50% by weight, based on the total weight of the polymer containing free carboxyl groups, the leachable multivalent ion source, and the strontium fluoride. A manufacturing method according to item 1. 3. The manufacturing method according to claim 1 or 2, wherein the leaching polyvalent metal ion source is acid-leaching glass. 4. Claim 3, characterized in that the acid-leaching glass is calcium aluminofluorosilicate glass.
Manufacturing method as described in section. 5. The manufacturing method according to any one of claims 1 to 4, wherein the polymer containing free carboxyl groups is a homopolymer or copolymer of acrylic acid. 6. The polymer containing free carboxyl groups has a molecular weight of 35
A method according to claim 5, characterized in that it is a homopolymer of acrylic acid having a molecular weight ranging from 1,000 to 70,000. 7. The manufacturing method according to any one of claims 1 to 6, wherein the glass has a particle size in the range of 0.5 to 60 μm. 8. A manufacturing method according to claim 1, which is essentially characterized by the method described in the Examples. 9. Forming the base, liner or subfiller according to the method described in any one of the preceding claims, and then forming one or more ethylenically unsaturated compounds, particulate fillers. and forming an overlaying filler over a secondary filler from a composite dental composition comprising a polymerization initiator for ethylenically unsaturated compounds. 10. Claim 9 comprising essentially the features described above.
Method according to section. 11. A dental restorative material comprising a polymeric matrix containing strontium fluoride. 12. The polymerization matrix is formed from a composite composition comprising one or more ethylenically unsaturated compounds, a particulate filler, and a polymerization initiator. dental restorative materials. 13. Dental restorative material according to claim 11, characterized in that the polymeric matrix is a polyacrylate dental cement. 14. A radiopaque resin structure containing strontium as a radiopaque agent. 15. The structure of claim 14, wherein strontium is the principal radiopaque agent. 16. The structure of claim 15, wherein strontium is virtually the only radiopaque agent. 17. Structure according to any one of claims 14 to 16, characterized in that the strontium is present as strontium fluoride. 18, per mm of structure, at least 1.
18. A structure according to any one of claims 14 to 17, characterized in that it has a radiopacity of 0 mm. 19. per mm of structure, at least 1.
19. Structure according to claim 18, characterized in that it has a radiopacity of 5 mm. 20, per mm of structure, at least 2.
20. A structure according to claim 19, characterized in that it has a radiopacity of 0 mm. 21. Structure according to any one of claims 14 to 20, characterized in that it is substantially translucent in nature.